This invention relates generally to packaging and more particularly to child-resistant blister packages.
Various packages have been disclosed in the patent literature and many are commercially available for holding one or more medicaments therein.
For example, U.S. Pat. No. 3,780,856 (Braverman) discloses a medicinal dispensing package comprising a base member having plurality of units, each made up of flanges having corners and surrounding a chamber for holding a drug therein. The units are detachably connected along perforated lines so that one flange may be separated from the others. A closure sheet having perforated lines corresponding to the perforated lines of the base member is secured, via areas of adhesive on it, to the flanges of the units to cover each unit. The central areas of the closure sheet disposed over each of the chambers do not have any adhesive. Selected comers of the base member are cut away so that one comer of the closure sheet overlying unit can be readily lifted as a tab to gain entry into the chamber.
In U.S. Pat. No. 4,398,634 (McClosky) there is disclosed a child-proof package system including multiple sealed units that are separately interconnected to one another by tear lines. Each of the units includes opposed, substantially planar, tear resistant flexible plastic sheets heat sealed to each other about peripheral seal zones to form a compartment for a drug. The seal zones between adjacent compartments include tear lines for permitting separation of discrete sealed units from each other without disrupting the integrity of the compartments. Each tear line includes a substantially linear, continuous slit uninterrupted by bridge areas and being linearly aligned with the compartments of adjacent units. The linear dimension of each of the continuous slits is greater than the greatest linear dimension of the linearly aligned compartments as measured parallel to the continuous slit.
In U.S. Pat. No. 5,551,567 (Malone et al.) there is disclosed a package having plural blister units, each of which includes a well adapted to hold a medicinal dosage therein. Score lines are surrounding each well to define the boundaries of each unit. A cover having plural score lines corresponding to the score lines of the blister is located over the blister to seal the dosage within the wells. Each of the units is separable from the other units by tearing it along its score lines. A short score line is provided in each blister unit and it extends into communication with the score lines separating the units. The short score line of each unit serves as the means for tearing an individual unit open to gain access to the dosage therein.
Other blister packages, some of which are disclosed to be xe2x80x9cchild-proofxe2x80x9d, are shown in the following United States Letters Patent Nos.: U.S. Pat. No. 4,011,949 (Braber et al.), U.S. Pat. No. 4,248,144 (Margulies), U.S. Pat. No. 4,294,361 (Margulies et al.), U.S. Pat. No. 4,398,635 (Hirt), U.S. Pat. No. 4,506,789 (Dlugosz), U.S. Pat. No. 4,537,312 (Intini), U.S. Pat. No. 5,046,618 (Wood), U.S. Pat. No. 5,172,812 (Wharton et al.), U.S. Pat. No. 5,310,060 (Bitner et al.), U.S. Pat. No. 5,325,968 (Sowden), U.S. Pat. No. 5,339,960 (Price), U.S. Pat. No. 5,469,968 (Matthews et al.), U.S. Pat. No. 5,472,093 (Nugent et al.), U.S. Pat. No. 5,529,188 (Coggswell), U.S. Pat. No. 5,613,609 (Hamilton et al.), U.S. Pat. No. 5,758,774 (Leblong), U.S. Pat. No. 5,775,505 (Vasquez et al.), U.S. Pat. No. 5,785,180 (Dressel), U.S. Pat. No. 5,862,915 (Plezia et al.), U.S. Pat. No. 5,878,887 (Parker et al.), U.S. Pat. No. 5,878,888 (Faughey et al.), U.S. Pat. No. 5,894,930 (Faughey et al.), U.S. Pat. No. 5,938,032 (Svec et al.) and U.S. Pat. No. 5,944,191 (Ray et al.)
While the packages of the foregoing patents may be generally suitable for their intended purposes, they each appear to leave something to be desired from the standpoint of providing a unt-dose package which is easy to open by an adult, but which is resistant to opening by a child (e.g., is xe2x80x9cchild-proofxe2x80x9d) is simple in construction and low in cost.
In accordance with one aspect of this invention there is provided a child-resistant blister package for unit dose products, e.g., medicaments. The package basically comprising a blister layer and a cover layer. The blister layer is formed of a planar material, e.g., thermoformable or cold-formable webstock, and has at least one perforated line and at least two cells or units contiguous with its perforated line. The cells of the blister layer have a peripheral planar flanged portion and a blister portion projecting from the flanged portion to form a cavity in which the unit dose product is to be located. The cover layer is formed of a planar material, e.g., aluminum or other metal foil in either a single ply or a lamination, and has at least one perforated line and at least two cells contiguous with its perforated line. Each cell of the cover layer is the same shape and size as a corresponding cell of the blister layer. The cover layer is fixedly, e.g., adhesively, secured to the blister layer along the flanged portions, with the at least one perforated line of the cover layer being coincident with the at least one perforated line of the blister layer and with the cells of the cover layer being coincident with the cells of the blister layer.
The blister layer additionally comprises a generally keyhole shaped opening in at least one of its cells. The keyhole shaped opening comprising an elongated, e.g., 3 mm, linear slit having a pair of ends and a hole, e .g., a 1 mm circular hole, at a first one of the pair of ends of the slit. The keyhole shaped opening is located in the cell of the blister layer so that the first one of said pair of ends is located adjacent but spaced by a gap of a predetermined length, e.g., approximately 1 mm, slightly from the at least one perforated line of the blister layer, and with the hole being located spaced, e.g., 4 mm, from but directed toward the cavity of that cell.
When so constructed the package is resistant to tearing by a child, but is tearable by an adult along the at least one aligned perforated lines and from there across the gap to the slit in the keyhole shaped opening.